What Are the Different Types of Diamonds?

13 August 2015

Diamonds are the most valued stones on earth. They consist of a clear and generally colorless crystalline form of sheer carbon. And carbon is the hardest naturally occurring substance around. This is why diamonds are used for other purposes besides jewelry such as phonograph and video disc needles, polishing hard metal, cutting tools like saws, drills and bearings for laboratory instruments. Crushed diamonds are also used in cutting other diamonds. In addition, only about 20% of diamonds are used for jewelry, the other 80% are used for industrial purposes.
Types of Diamonds

Unsurprisingly, diamonds are classified based on the type and quantity of impurities. For the most part, there are two main classifications of diamonds. Type I contains nitrogen atoms and Type II contains other impurities without nitrogen. Diamonds are also further classified into 4 types; Type Ia, Type Ib, Type IIa and Type IIb. Interestingly, one stone can be classified as more than one specific type of diamond.


Type I is the most common type of diamond. These stones contain nitrogen within the crystal structure. The Type I diamond has two categories: Type Ia and Type Ib.


The Type Ia is the most colorless stone. It has the addition of nitrogen atoms which is always in clusters throughout the stone. How the clusters are broken down will determine the color of the diamond. It is the most common class of diamond. About 98% are Type Ia. The Type Ia diamond has two sub-divided types:

Type IaA and Type IaB. These diamonds have a visible absorption spectrum and a distinctive fluorescence.

  • Type IaA: Composed of nitrogen atom pairs (A-aggregates). Absorbs no visible light and color is not affected.
  • Type IaB: Contains clusters of four nitrogen atoms (B-aggregates). Like Type IaA, it does not absorb any visible light and color is not affected.

    The majority of Type Ia diamonds are a combination of Type Ia, Type IaB and Type N3. As you may have guessed, the Type N3 contains three nitrogen atoms. However, Type N3 diamonds do absorb light.


Type Ib diamonds are composed of nitrogen atoms that are in singular form (not clusters). These types of diamonds are much rarer than Type Ia stones. The Type Ib diamond absorbs both blue and green lights. In addition, the tone of the color is a lot deeper and more intense. The most impressive colored diamonds on the market are Type Ib.


The Type II diamond does not contain nitrogen impurities. These type of diamonds are rarer than the Type I stones. As well, the Type II is much harder and bigger. The Type II diamond has two categories: Type IIa and Type IIb.

  • Type IIa: This type of diamond is the most sought after. Sometimes known as “Golconda”, it rarely has internal imperfections. The Type IIa is known for its color. Even the white stones are whiter than other types. This beautiful stones has very vivid red, orange, yellow, brown, purple or pink coloring.
  • Type IIb: Like the Type IIa, this diamond does not have nitrogen atoms (impurities). But, this stone does contain boron. But it is the boron that makes it exclusive. In truth, boron gives the Type IIb diamond a light blue or gray tone.

Ken Ross Jewellers

Established in 1954, Ken Ross Jewellers is renowned for producing and maintaining fine jewelry and watches. And over the decades, many awards have been won. Ken Ross Jewellers specializes in supplying fine jewelry like diamonds and semi-precious stones, plus repairs for rings, wedding bands and watches. For a valuation of a diamond you have, repairs on a wedding ring or new precious diamond jewelry, contact:

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